A combined numerical-experimental approach for the damping evaluation of nonlinear dissipative vibration systems

机械结构的动力学本质上受阻尼量的影响，而阻尼量可能具有非常不同的物理性质。除了材料阻尼外，还可用于摩擦连接，如螺栓和法兰、颗粒阻尼器、压电式阻尼器等。然而，阻尼值的准确预测仍然是一个悬而未决的问题。因此，在这个项目中，将开发一种方法，该方法基于对简单的非线性代理模型的研究，通过适当的模型简化技术产生。不同的非线性减振原理可以由局部附着到主体结构的所谓的非线性能量汇(NE)来表示。利用连续法、分叉分析、交变频率-时间法、多谐方法和稳定性分析等方法，对所得到的非线性替代模型进行了求解。作为主要结果，这些结果将使人们深入了解非线性减振装置的效率，特别是稳健性，以便评估其对具有不确定参数和不同运行条件的结构的适用性。数值研究将伴随着验证该方法的实验。

The dynamics of mechanical structures is essentially affected by the amount of damping, which may be of very different physical nature. Beside material damping these are e.g. in frictional joints such as bolts and flanges, particle dampers, piezo damping and much more. However, the accurate prediction of the damping values still is an open issue. Hence, in this project, a methodology will be developed that is based on the investigation of simple nonlinear surrogate models, resulting from appropriate model reduction techniques. Different nonlinear damping principles may be represented by so-called nonlinear energy sinks (NES) that are attached locally to the host structure. Special attention is paid on the solution of the obtained nonlinear surrogate models, applying procedures like continuation methods, bifurcation analysis, alternating frequency-time-methods, multiharmonic approaches and stability analysis. As a main outcome, the results will give insight in the efficiency and, in particular, the robustness of nonlinear damping devices, in order to evaluate their applicability to structures with uncertain parameters and varying operating conditions. The numerical studies will be accompanied by experiments to validate the methodology.